code: def __call__(self, key):
      return self._function(self._resource, key)
  
file_path: io/tensorflow_io/python/ops/lmdb_io_tensor_ops.py
imports: import uuid
  import tensorflow
  from tensorflow_io.python.ops import io_tensor_ops
  from tensorflow_io.python.ops import core_ops
label_desc: Use image node_id 2 for calling the _IOTensorMappingFunction obj's underlying member method code with example usage: obj.__call__(key) and returns: self